4pin Bluetooth Module HC-05 for Arduino
Features:
Input voltage 3.3v ~ 6v, module with 3V LDO voltage regulator
Support AT command set the baud rate, name, pair password
Search and pairing automatically when the power up
Power, link status indicator
4pin  2.54 Pitch status indicator
 
Note:
The default communication baud rate is 9600, matching the password is 0000 or 1234
Lights blinking when the search, When light means has been connected to the host device.
 
Performance parameters :
Sensitivity ( BER ) reaches -80dBm
-4> 6dBm adjustable output power
Bluetooth 2.0 with EDR, 2Mbps, 3Mbps
 
Modulation
Built-in 2.4GHz antenna user does not need to debug antenna
Built- 8Mbit FLASH
Low Voltage 3.3V Operating
Optional PIO control
Standard HCI port (UART or USB)
USB protocol : full Speed USB1.1, Compliant With 2.0)
Modules can be used as SMD chip technology
RoHS Process
Pin half hole 2.4GHZ wireless digital technology to close the transmitter
CSR BC04 l Bluetooth chip technology
Adaptive Frequency Hopping Technology
Bluetooth Class2 power level
Storage temperature : -40 to +85 degrees
Working temperature : -25 ~ +75 degrees
Hip -wave interference : 2.4MHz, transmit power 3dBm
BER : 0   but when generate a signal decay , will be error in the transmission link , such as RS232 and TTL.
Mechanical Dimensions : 34mm * 15mm * 3.2mm
 
AT command:
Testing Communications
  Send: AT (return OK, one second left and right once)
Returns: OK
 
Bluetooth serial communication baud rate change
Send: AT + BAUDI
Returns: OK1200
Send: AT + BAUD2
Returns: OK2400
 
BAUD1 --------- 1200
BAUD2 --------- 2400
BAUD 3 --------- 4800
BAUD 4 --------- 9600
BAUD 5 --------- 19200
BAUD 6 --------- 38400
BAUD 7 --------- 57600
BAUD 8 --------- 115200
BAUD 9 --------- 230400
BAUD A --------- 460800
BAUD B --------- 921600
BAUD C --------- 1382400
 
Interference causes system instability is not recommended for use in more than 115,200 baud. rate.
After setting more than 115,200 computer unusable ,use in microcontroller programming using this baud rate higher than 115200 in order to Re-issue the AT command set low baud
After the baud rate with AT command set , don't need re- setting the baud rate the next time .
It will saved after power off automatically.
 
3 Bluetooth name change
Send : AT + NAMEname
Returns : OKsetname
Parameter name: The name of the current to be set , the Bluetooth name is searched . Within 20 characters .
 
For example: sending AT + NAMEdagu  
 
Return OKsetname
 
At this time the name of the Bluetooth bill_gates
Parameters can be powered down to save , simply modify one . PDA client refresh services can be seen after the change of the name of the Bluetooth
   
4 Bluetooth pairing password change
       
Send : AT + PINxxxx
     
Returns : OKsetpin
       
Parameter xxxx: pairing password to be set ,4 bytes. 
This command can be used slave or master .
Machine is a phone adapter or pop-up window when asked to enter a passcode from the manual input of this parameter can be connected from the machine .
Primary Bluetooth module search from the machine, if the password is correct , it is automatically paired , in addition to the main module from the module can be connected to the outer pair
other products from the module contains the pair can be connected , for example, a digital camera containing Bluetooth , Bluetooth GPS, Bluetooth serial printers , and the like.
       
For example: sending AT + PIN8888
          
Return OKsetpin
 
Then the Bluetooth passkey is 8888 . Parameters can be powered down to save , simply modify once.